Superconducting articles, and methods for forming and using same

ABSTRACT

A superconducting tape is disclosed, including a substrate having a first surface and a second surface opposite the first surface, the substrate including a plurality of indicia provided on the first surface spaced apart along a length of the substrate; and a superconductor layer overlying the second surface. Also disclosed are components incorporating superconducting tapes, methods for manufacturing same, and methods for using same.

CROSS-REFERENCE TO RELATED APPLICATION(S) BACKGROUND

1. Field of the Invention

The present invention is generally directed to superconducting orsuperconductor components, and in particular, a novel superconductingtape, power components incorporating same, and methods for utilizing andmanufacturing same.

2. Description of the Related Art

Superconductor materials have long been known and understood by thetechnical community. Low-temperature (low-T_(c)) superconductorsexhibiting superconductive properties at temperatures requiring use ofliquid helium (4.2 K), have been known since about 1911. However, it wasnot until somewhat recently that oxide-based high-temperature(high-T_(c)) superconductors have been discovered. Around 1986, a firsthigh-temperature superconductor (HTS), having superconductive propertiesat a temperature above that of liquid nitrogen (77 K) was discovered,namely YBa₂Cu₃O_(7-x) (YBCO), followed by development of additionalmaterials over the past 15 years including Bi₂Sr₂Ca₂Cu₃O_(10+y) (BSCCO),and others. The development of high-T_(c) superconductors has broughtpotential, economically feasible development of superconductorcomponents incorporating such materials, due partly to the cost ofoperating such superconductors with liquid nitrogen, rather than thecomparatively more expensive cryogenic infrastructure based on liquidhelium.

Of the myriad of potential applications, the industry has sought todevelop use of such materials in the power industry, includingapplications for power generation, transmission, distribution, andstorage. In this regard, it is estimated that the native resistance ofcopper-based commercial power components is responsible for quitesignificant losses in electricity, and accordingly, the power industrystands to gain significant efficiencies based upon utilization ofhigh-temperature superconductors in power components such astransmission and distribution power cables, generators, transformers,and fault current interrupters. In addition, other benefits ofhigh-temperature superconductors in the power industry include anincrease in one to two orders of magnitude of power-handling capacity,significant reduction in the size (i.e., footprint) of electric powerequipment, reduced environmental impact, greater safety, and increasedcapacity over conventional technology. While such potential benefits ofhigh-temperature superconductors remain quite compelling, numeroustechnical challenges continue to exist in the production andcommercialization of high-temperature superconductors on a large scale.

Among the many challenges associated with the commercialization ofhigh-temperature superconductors, many exist around the fabrication of asuperconducting tape that can be utilized for formation of various powercomponents. A first generation of superconducting tapes includes use ofthe above-mentioned BSCCO high-temperature superconductor. This materialis generally provided in the form of discrete filaments, which areembedded in a matrix of noble metal, typically silver. Although suchconductors may be made in extended lengths needed for implementationinto the power industry (such as on the order of kilometers), due tomaterials and manufacturing costs, such tapes do not represent acommercially feasible product.

Accordingly, a great deal of interest has been generated in theso-called second-generation HTS tapes that have superior commercialviability. These tapes typically rely on a layered structure, generallyincluding a flexible substrate that provides mechanical support, atleast one buffer layer overlying the substrate, the buffer layeroptionally containing multiple films, an HTS layer overlying the bufferfilm, and an electrical shunt layer overlying the superconductor layer,typically formed of at least a noble metal. However, to date, numerousengineering and manufacturing challenges remain prior to fullcommercialization of such second generation-tapes.

Accordingly, in view of the foregoing, various needs continue to existin the art of superconductors, and in particular, provision ofcommercially viable superconducting tapes, methods for forming same, andpower components utilizing such superconducting tapes.

SUMMARY

According to one aspect of the invention, a superconducting article isprovided that includes a substrate having first and second surfacesopposite each other, and a superconductor layer overlying the secondsurface. According to this aspect, a plurality of indicia are providedon the first surface and spaced apart along a length of the substrate.The article may be in the form of a tape.

According to another aspect of the present invention, a method formanufacturing a superconductive tape is provided, including a substratehaving a first surface and a second surface opposite the first surface,the substrate including a plurality of indicia provided on the firstsurface and spaced along a length of the substrate. Further, the methodcalls for subjecting the substrate to multiple processing operations,which include providing a superconductor a layer to overlie the secondsurface, and inspecting the superconductive tape based on the indicia.In this regard, typically the inspecting of the superconductive tape iscarried out subsequent to at least one processing operation, andfollowing inspection additional processing operations may be carriedout. Alternatively, processing operations may be completed to form acomplete superconductive tape, followed by an inspection of the tapedbased on the indicia.

According to another aspect of the present invention, a power cable isprovided including a plurality of superconductive tapes, thesuperconductive tapes being provided in accordance with the first aspectof the present invention described above.

According to yet another aspect of the present invention, a powertransformer is provided including primary and secondary windings, atleast one of the windings including a wound coil of superconductive tapeprovided in accordance with the first aspect of the present invention.

According to yet another aspect of the present invention, a powergenerator is provided including a shaft coupled to a rotor whichcontains electromagnets comprising rotor coils, and a stator comprisinga conductive winding surrounding the rotor. The rotor coils and/or theconductive winding includes a superconductive tape generally inaccordance with the first aspect of the present invention describedabove.

According to yet another aspect of the present invention a power grid isprovided, which includes multiple components for generation,transmission and distribution of electrical power. Namely, the powergrid includes a power generation station including a power generator, atransmission substation including a plurality of power transformers forreceiving power from the power generation station and stepping-upvoltage for transmission, and a plurality of power transmission cablesfor transmitting power from the transmission substation. Distribution ofthe power is provided by utilization of a power substation for receivingpower from the power transmission cables, the power substationcontaining a plurality of power transformers for stepping-down voltagefor distribution, and a plurality of power distribution cables fordistributing power to end users. According to a particular feature ofthis aspect of the present invention, at least one of the power gridelements described above includes a plurality of superconductive tapes,provided in accordance with the first aspect of the present inventiondescribed above.

Still further, another aspect of the present invention provides a methodfor laying power cable, sometimes also referred to generically as“pulling” cable. The method calls for providing a coil of power cable,and unwinding the coil while inserting the power cable into a conduit,wherein the conduit is an underground utility conduit. The structure ofthe power cable is described above, namely, includes a plurality ofsuperconductive tapes in accordance with the first aspect of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerousobjects, features, and advantages made apparent to those skilled in theart by referencing the accompanying drawings.

FIG. 1 illustrates a substrate, a component of a superconducting tapeaccording to an embodiment of the present invention.

FIGS. 2–4 illustrate several different configurations of indiciaprovided on a first surface of the substrate.

FIG. 5 illustrates a layered structure of a superconducting tapeaccording to an embodiment of the present invention.

FIGS. 6 and 7 illustrate power cables incorporating superconductivetapes.

FIG. 8 illustrates a power-transformer.

FIG. 10 illustrates a power grid according to another aspect of thepresent invention.

The use of the same reference symbols in different drawings indicatessimilar or identical items.

DETAILED DESCRIPTION

According to a first embodiment of the present invention, asuperconducting tape is provided that includes a substrate having firstand a second opposite surfaces. In this regard, the attention is drawnto FIG. 1 illustrating substrate 10 having first surface 12 and secondsurface 14 opposing the first surface 12. The substrate 10 is typicallyin a tape-like configuration, having a high aspect ratio. For example,the width of the tape is generally on the order of about 0.4–10 cm, andthe length of the tape is typically at least about 100 m, most typicallygreater than about 500 m. Indeed, embodiments of the present inventionprovide for superconducting tapes that include substrate 10 having alength on the order of 1 km or above. Accordingly, the substrate mayhave an aspect ratio which is fairly high, on the order of not less than10³, or even not less than 10⁴. Certain embodiments are longer, havingan aspect ratio of 10⁵ and higher. As used herein, the term ‘aspectratio’ is used to denote the ratio of the length of the substrate ortape to the next longest dimension, the width of the substrate or tape.

According to a particular feature according to the present invention,the substrate is marked to have a plurality of indicia provided on aback surface of the substrate, which, in the drawings herein, isillustrated as first surface 12. According to this particular feature,the indicia are provided as marks that have varying configurations andwhich provide various functions including the capability of indexingvarious positions along an extended length of the substrate 10. Severalforms of indicia are provided in FIGS. 2–4. Generally speaking theindicia may contain several components, including a position identifierand a fiducial. As generally referred to herein, the term “indicia” isused in connection with the aggregate of indicia sets, each indicia setgenerally including position identifier, and often additionally afiducial.

A position identifier is a marking, which is a generally unique markingamong the indicia provided on a tape, which is correlated to aparticular position on the substrate. The position identifier may takeon various forms, such as bar code 16 shown in FIG. 2, a 2-dimensionalpattern such as a 2-dimensional matrix 18 as shown in FIG. 3, or analphanumeric code 22 as shown in FIG. 4. The indicia may be created soas to be read by automated means such as an optical reading system, ormanually by an operator through visual recognition. The positionidentifiers are generally coded in a way so as to indicate andcommunicate a unique position along a length of the superconductingtape.

In addition, the indicia typically include a fiducial. A fiducial is amarking that provides for accurate positioning of the tape, such asthrough an automated vision system that is set-up to recognize apre-determined shape. The fiducial may have different patterns, such asany of those widely used in commercially available vision systems. Forexample, a fiducial in the form of a hatching or cross-hair 18 is shownin FIG. 2. A star or asterisk 20 is shown in FIG. 3, and concentriccircles 24 are shown in FIG. 4.

According to aspects of the present invention, the incorporation ofindicia comprising indicia sets, each set including a positionidentifier and a fiducial, enables correlation of product quality toposition and tracking of position for the purpose of producttraceability. In these regards, highly precise location of a positionalong the substrate (and hence along the superconductive tape) isenabled by providing unique position identifiers that may bemachine-read or human-read and further aided by the implementation offiducials for precise positioning of the superconductive tape forvarious operations, such as processing operations or characterizationoperations at a particular location along the substrate. In this regard,generally speaking, the superconducting tape is handled in amanufacturing environment through various reel-to-reel processes andautomatic scanning of indicia provide a feedback mechanism which may beutilized for active control of the rotating reels used for productmanufacturing, characterization, testing and packaging.

Generally speaking, the indicia are spaced apart along the substrate ata generally constant interval or pitch, which is chosen to provideadequate resolution in data collection for the particular tape ofinterest. This pitch can be determined by statistical sampling or it canbe determined by engineering assessment as required for the purpose athand. Suitable pitches may be within a range of about 0.5 m to 100 m,for example. While in some cases the indicia may not span the entirelength of the substrate from beginning to end, typically, the indiciaspan a fairly substantial portion of the tape, such as at least about50% of the tape if not greater than about 60, 70, or even 80% of thetape. In a manufacturing setting, the use of indicia as described hereinhelps enable repeatable and accurate measurements of product quality atvarious positions along the length of the tape, such as after depositionprocesses to form the various layers of the superconducting tape.Typically, to enable such repeatability and accuracy, vision systems areincorporated into the manufacturing process and measurement tools sothat position can be correlated to corresponding quality data. Returningto a given specific location along the tape to conduct further qualitymeasurements can be easily accomplished by locating the appropriateposition identifier and fiducial.

According to a particular embodiment, the indicia are present only alongthe back surface (first surface) of the substrate, and do not extendinto the opposing, second surface. This is particularly important toprevent unwanted aberrations or defects in the second surface of thesubstrate, on which various highly sensitive layers are deposited toform a complete superconducting tape. Accordingly, typical mechanicaldeformation operations which imprint a pattern through physicaldeformation of the back surface of the substrate generally have to beimplemented in such a manner so as to leave the front surface intact, orotherwise such techniques are to be generally avoided.

Examples of suitable marking techniques include laser scribing,mechanical etching, chemical etching, plasma etching, or ion beametching, and ink printing. Of the foregoing, it is typically generallydesirable to incorporate a marking system which is a subtractiveprocess, that is, a process which removes material from the back surfaceof the substrate to form recesses. In this regard, recesses are lesslikely to be negatively altered through manufacturing and tape-handling,since the back side of the substrate typically slides against andcontacts various structural components during reel-to-reel processingand handling. More precisely, it is generally desirable that the indiciabe able to withstand dynamic physical contact with heating and coolingsurfaces during deposition processes, which at times may cause scratchesand abrasions along the back side of the tape along which the marksreside. Markings that protrude from the back surface, such as by inkprinting or screening, should be integrated along the back surface in arobust manner so as to survive manufacturing and handling conditions. Itis also noted that at times the superconducting tape is subjected torelatively high-temperature processes such as on the order of 500–1,000°C., optionally in oxidizing environments. Accordingly, the markingtechnique should also be thermally and chemically robust to survive suchprocessing conditions.

Chemical or mechanical etching may be carried out by provision of a maskalong the tape and exposing desired areas to the etching process byphysical or chemical means to remove material, creating images in theback side of the tape. Laser scribing, such as by ablation or meltingmay also be easily implemented. In this regard, a focused laser beam isinitiated so as to contact the back side, at an appropriate power toinduce surface ablation and/or material flow to form images on the backside of the tape.

According to one embodiment, incoming raw tape (substrate) prior to HTSprocessing is inspected and marked with a laser ablation process, atconstant intervals with a fiducial and a position identifier asdescribed above. The power of the laser is maintained to preventunwanted alteration of the front side of the tape. Automatic markreading systems are installed in the fabrication tools, which areconfigured to automatically read and process markings as they pass by,such as in a reel-to-reel process, thereby reporting position and/ortape lot information with process data at all or at selected points orpositions along the tape.

While the foregoing has mainly focused upon including at least one of aposition identifier and a fiducial, the indicia, namely the indiciasets, may further include a lot identifier. In this case, the lotidentifier may be a marking which marks a tape with a unique lotidentifier, so as to distinguish one tape from another tape, ordistinguish one lot of tapes from another lot of tapes. In this way,individual tapes may be distinguished from each other and the lotidentifier may be linked to specific date and/or process informationrelevant to that particular tape or lot of tapes. The lot identifier maybe incorporated into each indicia set, or only a selected set or sets.The use of lot identifiers may be particularly useful in providingtechnical support to end users or integrators, and may aid introubleshooting technical issues with a particular tape. The data mayalso be utilized to provide real-time feedback from integrators or endusers on performance, durability, etc., such that particularmanufacturing process parameters associated with different lots may beevaluated and modified as necessary to further improve product quality.

According to aspects of the present invention, incorporation of indiciaas described above enables provision of reliable methods to track tapeduring processing (manufacturing operations), so that variations inperformance of the HTS coated conductor can be traced back to thesource. In addition, tracking through use of the indicia may also bebeneficial in providing information on specific segments of a conductorto end users, including customers such as commercial integrators orentities responsible for maintaining and/or operating a power grid orportions thereof, for whatever reasons such users may have. In theseregards, description of product quality or performance is generally usedto include any one of or multiple important characteristics of thesuperconducting tape, which include electromagnetic, mechanical andmicrostructural properties. Electromagnetic properties may includecritical current I_(c), critical current density J_(c), transitiontemperature T_(c), and others. Mechanical properties may include stress,strain, and others. Microstructural properties may include crystaltexture, surface roughness, composition, film thickness, and others.

The present superconducting tape including a marking scheme includingindicia as described herein provides numerous advantages over the stateof the art. In this regard, in general, marking of wires is commonlydone by ink printing through stamping, screening or jet printing, orother marking techniques. Typically, such marks are used for indicatingproduct brand identification, part number ID, physical size (such asgauge), etc. Such commonly used marking schemes do not provide uniqueidentifiers for finding specific or unique locations along a length ofmaterial.

More specifically, coated conductors are conventionally marked at thebeginning and/or end of the conductor. When measurements are made,returning to a specific point along the coated conductor relies onwinding and un-winding the material over encoder wheels to provide areadout of length. These state of the art encoders are typically highlycalibrated to within a +/−0.1% accuracy. However, at extended lengthssuch as 1 kilometer, the desired position can be off my as much as 1meter, making correlation of position to quality extremely difficult ifnot impossible. Additionally, reliance upon end-marking is subject tohandling mishaps, such as when the end of a mark gets removed or“cut-off,” losing the reference point permanently. On the other hand,the built-in redundancy of position identifiers and fiducial marks,along with a complementary optical recognition system for location, aninspection device can typically return to within 500 microns, mosttypically return within 100 or even 25 microns to a desired preciseposition along the tape, irrespective of the length of tape. Suchprecision represents a 40,000× improvement in location accuracy comparedto state of the art marking techniques.

Turning to FIG. 5, the general layered structure of an HTS conductoraccording to an embodiment of the present invention is depicted. Inaddition to substrate 10, the HTS conductor typically includes a bufferlayer 30 overlying the second surface 14 of the substrate, an HTS layer32, followed by an noble metal layer 34. The buffer layer may be asingle layer, or more commonly, be made up of several layers. Mosttypically, the buffer layer includes a biaxially textured film, having acrystalline texture that is generally aligned along crystal axes bothin-plane and out-of-plane of the film. Such biaxial texturing may beaccomplished by IBAD. As is understood in the art, IBAD is acronym thatstands for ion beam assisted deposition, a technique that may beadvantageously utilized to form a suitably textured buffer layer forsubsequent formation of an HTS layer having desirable crystallographicorientation for superior superconducting properties.

The high-temperature superconductor (HTS) layer 32 is typically chosenfrom any of the high-temperature superconducting materials that exhibitsuperconducting properties above the temperature of liquid nitrogen, 77K. Such materials may include, for example, YBa₂Cu₃O_(7-x),Bi₂Sr₂Ca₂Cu₃O_(10+y), Ti₂Ba₂Ca₂Cu₃O_(10+y), and HgBa₂ Ca₂Cu₃ O_(8+y).One class of materials includes REBa₂Cu₃O_(7-x), wherein RE is a rareearth element. Of the foregoing, YBa₂Cu₃O_(7-x), also generally referredto as YBCO, may be advantageously utilized.

The noble metal layer 34 is generally implemented for electricalshunting, to aid in prevention of HTS burnout in practical use. Moreparticularly, layer 34 aids in continued flow of electrical chargesalong the HTS conductor in cases where cooling fails or the criticalcurrent density is exceeded, and the HTS layer moves from thesuperconducting state and becomes resistive. Typically, a noble metal isutilized for layer 34 to prevent unwanted interaction between noblemetal layer 34 and the HTS layer 32. However, the noble metal layer 34may be supplemented with more cost efficient conductive materials, suchas copper, overlying noble metal layer 34.

Moving away from the particular structure of the superconducting tape,FIGS. 6 and 7 illustrate implementation of a superconducting tape in acommercial power component, namely a power cable. FIG. 6 illustratesseveral power cables 42 extending through an underground conduit 40,which may be a plastic or steel conduit. FIG. 6 also illustrates theground 41 for clarity. As is shown, several power cables may be runthrough the conduit 40.

Turning to FIG. 7, a particular structure of a power cable isillustrated. In order to provide cooling to maintain the superconductivepower cable in a superconducting state, liquid nitrogen is fed throughthe power cable through LN2 duct 44. One or a plurality of HTS tapes 46is/are provided so as to cover the duct 44. The tapes may be placed ontothe duct 44 in a helical manner, spiraling the tape about the duct 44.Further components include a copper shield 48, a dielectric tape 50 fordielectric separation of the components, a second HTS tape 52, a coppershield 54 having a plurality of centering wires 56, a second, larger LN2duct 58, thermal insulation 60, provided to aid in maintaining acryogenic state, a corrugated steel pipe 62 for structural support,including skid wires 64, and an outer enclosure 66.

FIG. 8 illustrates schematically a power transformer having a centralcore 76 around which a primary winding 72 and a secondary winding 74 areprovided. It is noted that FIG. 8 is schematic in nature, and the actualgeometric configuration of the transformer may vary as is wellunderstood in the art. However, the transformer includes the basicprimary and secondary windings. In this regard, in the embodiment shownin FIG. 8, the primary winding has a higher number of coils than thesecondary winding 74, representing a step-down transformer that reducesvoltage of an incoming power signal. In reverse, provision of a fewernumber of coils in the primary winding relative to the secondary windingprovides a voltage step-up. In this regard, typically step-uptransformers are utilized in power transmission substations to increasevoltage to high voltages to reduce power losses over long distances,while step-down transformers are integrated into distributionsubstations for later stage distribution of power to end users. At leastone of and preferably both the primary and secondary windings comprisesuperconductive tapes in accordance with the foregoing description

Turning to FIG. 9, the basic structure of a generator is provided. Thegenerator includes a turbine 82 connected to a shaft 84 for rotatablydriving a rotor 86. Rotor 86 includes high-intensity electromagnets,which are formed of rotor coils that form the desired electromagneticfield for power generation. The turbine 82, and hence the shaft 84 andthe rotor 86 are rotated by action of a flowing fluid such as water inthe case of a hydroelectric power generator, or steam in the case ofnuclear, diesel, or coal-burning power generators. The generation of theelectromagnetic field generates power in the stator 88, which comprisesat least one conductive winding. According to a particular feature ofthe embodiment, at least one of the rotor coils and the stator windingcomprises a superconductive tape in accordance with embodimentsdescribed above. Typically, at least the rotor coils include asuperconductive tape, which is effective to reduce hysteresis losses.

Turning to FIG. 10, a basic schematic of a power grid is provided.Fundamentally, the power grid 110 includes a power plant 90 typicallyhousing a plurality of power generators. The power plant 90 iselectrically connected and typically co-located with a transmissionsubstation 94. The transmission substation contains generally a bank ofstep-up power transformers, which are utilized to step-up voltage of thegenerated power. Typically, power is generated at a voltage level on theorder of thousands of volts, and the transmission substation functionsto step-up voltages be on the order of 100,000 to 1,000,000 volts inorder to reduce line losses. Typical transmission distances are on theorder of 50 to 1,000 miles, and power is carried along those distancesby power transmission cables 96. The power transmission cables 96 arerouted to a plurality of power substations 98 (only one shown in FIG.10). The power substations contain generally a bank of step-down powertransformers, to reduce the transmission level voltage from therelatively high values to distribution voltages, typically less thanabout 10,000 volts. A plurality of further power substations may also belocated in a grid-like fashion, provided in localized areas forlocalized power distribution to end users. However, for simplicity, onlya single power substation is shown, noting that downstream powersubstations may be provided in series. The distribution level power isthen transmitted along power distribution cables 100 to end users 102,which include commercial end users as well as residential end users. Itis also noted that individual transformers may be locally provided forindividual or groups of end users. According to a particular feature, atleast one of the generators provided in the power plant 90, thetransformers and the transmission substation, the power transmissioncables, the transformers provided in the power substation, and the powerdistribution cables contain superconductive tapes in accordance with thepresent description.

While particular aspects of the present invention have been describedherein with particularity, it is well understood that those of ordinaryskill in the art may make modifications hereto yet still be within thescope of the present claims.

1. A superconducting article, comprising: a substrate having a firstsurface and a second surface opposite the first surface, the substrateincluding a plurality of indicia provided on the first surface spacedapart along a length of the substrate at a constant pitch; and asuperconductor layer overlying the second surface.
 2. The superconductorarticle of claim 1, wherein the article is a superconducting tape. 3.The superconducting article of claim 2, wherein the substrate has anaspect ratio of not less than 10³.
 4. The superconducting article ofclaim 2, wherein the substrate baa an aspect ratio of not less than 10⁴.5. The superconducting article of claim 1, wherein the constant pitch iswithin a range of about 0.5 m to 100 m.
 6. The superconducting articleof claim 1, wherein the indicia are spaced apart along substantially theentire length of the substrate.
 7. The superconducting article of claim1, wherein the indicia are preset only along the first surface, and donot extend into the second surface.
 8. The superconducting article ofclaim 1, wherein the indicia are made by at least one process from thegroup consisting of: laser scribing, mechanical etching, chemicaletching, ink printing, plasma etching, or ion beam etching.
 9. Thesuperconducting article of claim 1, wherein the indicia are made by amaterial subtractive process such that the indicia comprise recesses inthe first surface.
 10. The superconducting article of claim 1, whereineach indicia comprises an indicia set, each indicia set includingposition identifier.
 11. The superconducting article of claim 10,wherein the position identifier comprises a bar code.
 12. Thesuperconducting article of claim 10, wherein the position identifierincludes a 2-dimensional pattern.
 13. The superconducting article ofclaim 10, wherein the position identifier comprises an alphanumericcode.
 14. A superconducting article, comprising: a substrate having afirst surface and a second surface opposite the first surface, thesubstrate including a plurality of indicia provided on the first surfacespaced apart along a length of the substrate, each indicia comprising anindicia set including a unique position identifier; and a superconductorlayer overlying the second surface.
 15. The superconducting article ofclaim 10, wherein each indicia set further includes a fiducial forpositioning the article.
 16. The superconducting article of claim 15,wherein the fiducial is adapted for detection by an optical imagingsystem.
 17. The superconducting article of claim 16, wherein thefiducial comprises a marking consisting of at least one of the followingshapes: a star, concentric circles, and a crosshair.
 18. Thesuperconducting article of claim 10, wherein each indicia set furtherincludes a lot identifier.
 19. The superconducting article of claim 18,wherein the lot identifier includes manufacturing or processing datedata.
 20. The superconducting article of claim 1, wherein thesuperconductor layer comprises a high temperature superconductormaterial, having a critical temperature T_(c) not less than about 77 K.21. The superconducting article of claim 1, wherein the superconductormaterial comprises REBa₂Cu₃O_(7−x), wherein RE is a rare earth element.22. The superconducting article of claim 21, wherein the superconductormaterial comprises YBa₂Cu₃O₇.
 23. The superconducting article of claim1, further comprising a buffer layer provided between the superconductorlayer and the substrate.
 24. The superconductor article of claim 23,wherein the buffer layer includes at least one buffer film, the bufferfilm comprising a biaxially textured material having generally alignedcrystals both in-plane and out-of-plane of the film.
 25. Thesuperconducting article of claim 1, further comprising a noble metallayer overlying the superconductor layer.
 26. The superconductingarticle of claim 25, wherein the noble metal layer comprises silver. 27.The superconducting article of claim 1, wherein the article is a powerdevice comprising a superconductive tape, the superconductive tapecomprising said substrate and said superconductive layer.
 28. Thesuperconducting article of claim 27, wherein the power device is a powercable, said power cable comprising a plurality of superconductive tapes.29. The superconducting article of claim 28, further comprising aconduit for passage of coolant fluid.
 30. The superconducting article ofclaim 29, wherein the superconductive tapes are wrapped around theconduit.
 31. The superconducting article of claim 28, wherein the powercable comprises a power transmission cable.
 32. The superconductingarticle of claim 28, wherein the power cable comprises a powerdistribution cable.
 33. The superconducting article of claim 27, whereinthe power device is a power transformer, the power transformercomprising a primary winding and a secondary winding, wherein at leastone of the primary winding and secondary winding is comprised of saidsuperconductive tape.
 34. The superconducting article of claim 33,wherein the secondary winding has a fewer number of windings than theprimary winding, for reducing voltage.
 35. The superconducting articleof claim 33, wherein the primary winding has a fewer number of windingsthan the secondary winding, for increasing voltage.
 36. Thesuperconducting article of claim 27, wherein the power device is a powergenerator, the power generator comprising a shaft coupled to a rotorcomprising electromagnets containing rotor coils, and a statorcomprising a conductive winding surrounding the rotor, wherein at leastone of the winding and the rotor coils comprises said superconductivetape.